IdentityHashMap類isEmpty()方法 (IdentityHashMap Class isEmpty() method)

• isEmpty() method is available in java.util package.

  isEmpty()方法在java.util包中可用。

• isEmpty() method is used to check whether this IdentityHashMap is "empty" or "not empty".

  isEmpty()方法用于檢查此IdentityHashMap是“空”還是“非空”。

• isEmpty() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  isEmpty()方法是一個非靜態方法，只能通過類對象訪問，如果嘗試使用類名稱訪問該方法，則會收到錯誤消息。

• isEmpty() method does not throw an exception at the time of checking the empty status of this IdentityHashMap.

  在檢查此IdentityHashMap的空白狀態時， isEmpty()方法不會引發異常。

Syntax:

句法：

public boolean isEmpty();

Parameter(s):

參數：

• It does not accept any parameter.

  它不接受任何參數。

Return value:

返回值：

The return type of the method is boolean, it returns true when this IdentityHashMap is "empty" or "non-empty".

該方法的返回類型為boolean ，如果此IdentityHashMap為“空”或“非空”，則返回true。

Example:

例：

// Java program to demonstrate the example // of boolean isEmpty() method of IdentityHashMap import java.util.*;public class IsEmptyOfIdentityHashMap {public static void main(String[] args) {// Instantiates a IdentityHashMap objectMap < Integer, String > map = new IdentityHashMap < Integer, String > ();// By using put() method is to add// key-value pairs in a IdentityHashMapmap.put(10, "C");map.put(20, "C++");map.put(50, "JAVA");map.put(40, "PHP");map.put(30, "SFDC");// Display IdentityHashMapSystem.out.println("IdentityHashMap: " + map);// By using isEmpty() method is to// check whether this IdentityHashMap is// empty or notboolean status = map.isEmpty();// Display statusSystem.out.print("map.isEmpty(): ");System.out.println(status);} }

Output

輸出量

IdentityHashMap: {20=C++, 40=PHP, 50=JAVA, 30=SFDC, 10=C} map.isEmpty(): false

翻譯自: https://www.includehelp.com/java/identityhashmap-isempty-method-with-example.aspx

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